Multibarrel gun



July 31, 1956 J. R. BIRD 2,756,639

MULTIBARREL GUN Filed NOV. 21, 1952 2 Sheets-Sheet l Zlwucmiom John. R Bird July 31, 1956 J. R. BIRD 2,756,639

MULTIBARREL. GUN

Filed NOV. 21, 1952 2 Sheets-Sheet 2 Qwumfow John R-Birc I z 40 .29 #79 25 M03? United States Patent MULTIBARREL GUN John R. Bird, Belmont, Mass., assignor to the United States of America as represented by the Secretary of the Army Application November 21, 1952, Serial No. 321,959

'13 Claims. (Cl. 89-126) (Granted under Title 35, U. S. Code (1952), see. 266) The invention described herein may be manufactured and used by or for the Government for governmental purposes without the payment to me of any royalty thereon.

My invention relates to an improvement in the construction of guns and principally to that type of machine gun or firearm known as a Gatling gun in which a plurality of barrels are arranged around a common axis and provided with a suitable mechanism for feeding ammunition or cartridges thereto. My invention specifically is directed toward the discharge of the barrels in sequence in a predetermined position and the use of the propellent gas pressure generated in the barrel as a means of revolving the same to thereby present the next barrel in the predetermined sequence in firing position.

It is accordingly a broad object of my invention to improve on machine guns of the Gatling type.

It is a further and more specific object of my invention to provide a mechanism to utilize the propellent gas pressure to rotate the barrel assembly of a multibarrel gun.

Other objects and advantages will appear in the following specification in which:

Figure 1 is a perspective view of the novel gun barrel assembly embodying my invention.

Figure 2 is an end view of my gun barrel assembly.

Figure 3 is a longitudinal elevation partly in section taken on lines 33 of Figure 2 and looking in the direction of the arrows.

Figure 4 is a longitudinal elevation partly in section of a species of my invention.

Figure 5 is an end view taken on lines 55 of Figure 4 and looking in the direction of the arrows.

Figure 6 is an enlarged perspective view of a detail of my invention.

Figure 7 is an enlarged longitudinal elevation partly in section taken on lines 77 of Figure 5 and looking in the direction of the arrows.

Figure 8 is an elevation partly in section showing a modification of a detail of my invention.

Referring now to Figure 1 wherein like parts are designated by like reference characters, 1 indicates a generally cylindrical casing carrying trunnions 5 and enclosing a suitable cartridge feeding mechanism (not shown) and closed at the front end thereof by plate 4. Reference characters 2, 7, 9 and 14 indicate a plurality of barrels arranged in equiangularly spaced relation around a common axis and piercing plate 4 to extend within the cartridge feeding mechanism casing 1. It will, of course, be understood that although four barrels are here shown in the interests of clarity of detail any number limited only by structural requirements, may be utilized in the present invention. A tube 3 is provided piercing the center of plate 4 at one end thereof and extending forward together with the barrels through rotatable disc 20 which acts to provide radial stability and to thereby prevent barrel whip during the firing cycle. Disposed within and coaxial with rotatable tube 3 is shaft pin 6 which is secured against movement at the proximal end within casing 1 and ex- "ice tending beyond the terminal of tube 3 at the distal end thereof substantially as shown. A portion of the shaft 6 is cut away and constructed to provide an eccentric pin 8 which has the surface thereof machined to form a journal for a purpose that will presently be explained. Securely fixed to each barrel 2 of the gun is a cylinder 10 having a port at or near the head end and aligned with a cavity it formed in each barrel to provide a free flow of propellent gases. Fitted within the cylinder and in gastight sliding relation therewith is a piston 12 having a connecting rod 15 and a split bearing 16 embracing pin 3 for rotation thereabout. As is best seen in Figure 3 the several split bearings are juxtaposed axially of the pin 8 but it will be understood that a single bearing receiving all of the connecting rods may be readily utilized.

The operation of my weapon is as follows: When a cartridge is fed to the breech of barrel 2 which is in the firing position and exploded therein the projectile travels down the barrel in the usual manner and the pressure in the barrel after the projectile has passed the cavity 11 and before it issues from the muzzle acts upon the piston 19 tending to force it down. The piston cannot move axially because pin it is fixed against movement and therefore the pressure within the cylinder acting with undiminished force in all directions tends to displace the cylinder. Since the cylinder is firmly fixed to the barrel the resolution of forces between the pressure acting on the piston and the angular disposition of the pin 8 gives a component of force substantially at right angles to the axis of the cylinder. This force component is great enough to cause rotation of plate 20 together with the barrels and the cylinders secured thereto. As each cylinder sweeps through its arcuate path it carries its piston and connecting rod with it, rotation of the rods about pin 8 being permitted by the several split bearings. It will be readily seen that the center of rotation of the cylinders is the center of shaft 6, and the center of rotation of the corresponding pistons is the center of pin 3. As the assembly rotates, then, barrel 7 approaches the firing position vacated by barrel 2 and coincidentally therewith its piston is forced upward within the cylinder toward the head thereof by the eccentricity of displacement of the centers of rotation of the cylinders and the pistons. It is apparent that the stroke of the piston is a function of the degree of eccentricity between the centers of rotation. When barrel 7 has reached the firing position formerly occupied by barrel 2 a cartridge is fed thereto and exploded, whereby the piston and cylinder are in turn acted against and further angular motion is imparted to the assembly. As long, therefore, as cartridges are fed to the barrels the weapon will continue to fire and the barrels will present themselves in turn to the firing position.

Referring now to Figures 4, 5 and 6 wherein a further modification of my invention is disclosed, reference character 1, indicates a generally cylindrical casing carrying trunnions 5 and enclosing the cartridge feeding mechanism of any well known type (not shown). End plate it closes the forward end of the casing and is pierced by barrels 2, 7, 9 and 14 which extend forward to penetrate disc 2%. Elongated pin 21 is securely fixed within casing 1 at one end thereof and passes through disc 20. A ball bearing 22 is provided to allow relative rotation between the fixed pin 21 and the rotatable disc 20 whereby barrel whip during the firing cycle is reduced or substantially elim inated. Firmly fixed to each of the several barrels are elongated cylinders 23, 24, 25 and 26 adapted to receive pistons 28 in sliding relation therewith and connected by ports 27 to the interior of the barrel. Fixed to each piston for motion therewith is a connecting rod 29 with a bifurcated end 30 adapted to receive roller tappet 32 which rides on the outer face 33 of crown cam 34 as will later 3 appear. The cam 34 is fastened against motion by spider 35 attached to pin 21.

In operation the organization is so arranged that a cartridge is fed to the barrel whose roller tappet is at the apex of the crown cam so that when the explosion occurs and the projectile travels down the barrel in the usual manner a pressure is introduced into the cylinder for the interval of time that it takes the projectile to travel from the gas port to the muzzle. The as pressure acting upon the piston tends to displace it in a manner similar to the operation of an internal combustion engine cylinder. The downward acting force urging the roller tappet against crown. cam 33 causes a force component tending to rotate the entire barrel assembly, whereby the next barrel presents itself into the predetermined firing position and the cycle is thus repeated. Springs 36 insure engagement between the roller tappets and the cam face 33 and 1?, dily compress when the barrel moves toward the firing position. Since the barrels sweep through a circular path each roller tappet will maintain its position as it moves on the face; however, it will be understood that, if desired. the ends of bifurcations 30 may be extended over the side surfaces of cam 34 to embrace the same with a smooth sliding fit and thereby assure that each roller remains in the tangential plane, as shown upon Figures 4 and 7 as it traverses the cam face. Also, these ends may be turned inwardly to slidably fit Within grooves or channels (not shown) in the sides of the cam and paralleling the face thereof, whereby the rollers will be positively held in contact with the cam face at all times.

Referring now to Figure 8 it will be noted that a novel piston 39 is shown whereby positive motion of the connecting rod and roller is insured. The pressure existing in the barrel (hiring the short period from the time the projectile uncovers the gas port until it emerges from the barrel acts to give the effect of a hammer blow upon the piston. In order to obtain greater efiiciency through lengthening the time of impressed force the piston 39 is provided with a hollowed out face generally in the shape of a cup 4i) which constricts into a narrow turned passage 42 adapted to mate with gas port 27. It will be readily seen that the propellent gas will pass through passage 42 and into flaring cup portion 40. As the piston 39 moves to the right, as shown in the drawing, it will cover port 27 and prevent the escape of gas from cup 40 back into the barrel when the projectile has passed beyond the muzzle and the pressure therein has dropped. The entrapped gas will expand and force the piston and rod to move, whereby a steady force is imparted and the duration of impressed force is not dependent upon the time of projectile travel. After the gas has acted upon the piston it can escape through port 27; or a separate exhaust port (not shown) may be provided to determine the working portion of each stroke.

While I have shown my invention as applied to a Gatling gun it may be applied to any othher gun in which the barrels rotate about a common axis and the barrels are fixed in succession at one point of their circuit. I therefore desire it to be understood that I do not confine myself to the precise details of construction and arrangement of the invention as herein set forth, as modifications and variations may be made without departing from the spirit of the invention as defined by the appended claims.

I claim:

1. In a breech loading gun of the type in which a series of barrels revolve around a common axis to fire in sequence in a predetermined position, a propellent gas receiving chamber fixed to each of the said barrels and communicating therewith, and movable means within each of said chambers connected to fixed means external to said chambers whereby upon discharge of a barrel in the said predetermined position the propellent gas acts upon the said movable means to revolve the said series of barrels and present the successive barrel in the said predetermined position.

2. In a breech loading gun of the type in which a plurality of barrels revolve in a predetermined direction around a common axis to fire sequentially in a predetermined position, a propellent gas receiving chamber fixed to each of said barrels and communicating therewith, and movable means within each of said chambers connected to fixed means external to said chambers whereby upon discharge of a barrel in the said predetermined position the propellent gas acts upon the said movable means to revolve the said plurality of barrels and to present the successive barrel in the said predetermined position.

3. In a breech loading gun of the type in which a plurality of barrels revolve in a predetermined direction around a common axis to fire sequentially in a predetermined position, a propellent gas receiving chamber fixed to each of said barrels and communicating therewith, a piston slidable in each of said chambers and in gas tight relation therewith and connected to a fixed means external to the said chamber whereby upon discharge of a barrel in the said prede crmined position the propellent gas acts upon the said piston and chamber to revolve the said plurality of barrels and to present the successive barrel in the said predetermined position.

4. In a breech loading gun of. the type in which a plurality of barrels revolve in a predetermined direction around a common axis to fire sequentially in a predetermined position, a cylinder fixed to each barrel and communicating therewith, a piston slidable in each of said cylinders and in gas tight relation therewith, a red connected to said piston and engaging a stationary member whereby upon discharge of a barrel in said predetermined position the propellent gas acts upon the said piston and the said cylinder to exert a force upon said stationary member to revolve the said plurality of barrels and to present the successive barrel in the said predetermined position.

5. In a breech loading gun of the type in which a plurality of barrels revolve in a predetermined direction around a common axis to fire sequentially in a predetermined position, a cylinder fixed to each of said barrels and communicating therewith, the longitudinal axes of the cylinders being in separate planes at right angles to the said common axis, a piston slidable in each of the said cylinders and in gas tight relation therewith, connecting rods pivotally secured to the said pistons, an elongated pin disposed in the said common axis and fixed against movement at one end thereof and formed into an eccentric journal at the other end, said connecting rods joined to the said journal for rotation thereabout whereby upon discharge of a barrel in said predetermined position the propellent gas acts upon the said piston and the said cylinder to exert a force upon the said eccentric journal to revolve the said plurality of barrels and to present the successive barrel in the said predetermined position.

6. In a breech loading gun of the type in which a plurality of barrels revolve in a predetermined direction around a common axis to fire sequentially in a predetermined position, a cylinder fixed to each of said barrels and communicating therewith, the longitudinal axes of the cylinders being in separate planes disposed at right angles to the said common axis, a slidable piston in each of the said cylinders and in gas tight relation therewith, a connecting rod pivotally secured at one end thereof to each of the said pistons and formed into a bearing at the other end, an elongated rod disposed in the said common axis and secured against rotation at one end thereof and formed into an eccentric journal at the other end, the said bearings joined to the said journal for rotation thereabout and disposed in respective separate planes whereby upon discharge of a barrel in said predetermined position the propellent gas acts upon the said piston and the said cylinder to exert a force through the said connecting rod to the said eccentric journal to revolve the said plurality of barrels and to present the successive barrel in the said predetermined position.

7. The invention according to claim 6 wherein the said piston is a hollow shell with a forward flaring portion to receive and entrap a part at least of the propellent gas from the said barrel.

8. In a gun of the type in which a plurality of barrels revolve in a predetermined direction around a common axis to fire sequentially in a predetermined position, a cylinder fixed to each of said barrels and communicating therewith, the axis of the said cylinder disposed parallel to and radially displaced from the respective axis of the barrel, a slidable piston in each of the said cylinders and in gas tight relation therewith, a connecting rod secured at one end thereof to the respective piston and terminating in a bifurcation at the other end adapted to receive a tappet, a crown cam concentric with the said common axis and formed with a face for cooperation with the said tappets, whereby upon discharge of a barrel in the said predetermined position the propellent gas acts upon the said piston and the said cylinder to exert a force through the said connecting rod to the said crown cam to revolve the said plurality of barrels and to present the successive barrel in the said predetermined position.

9. The invention according to claim 8 wherein the said piston is a hollow shell with a forward flaring portion to receive and entrap a part at least of the propellent gas.

10. In a breech loading gun of the type in which a plurality of barrels revolve in a predetermined direction around a common axis to fire sequentially in a predetermined position, a cylinder fixed to each of said barrels and communicating therewith, the longitudinal axes of the cylinders being in separate planes at right angles to the said common axis, a piston slidable in each of the said cylinders and in gas tight relation therewith, connecting rods pivotally secured to the said pistons, an elongated pin disposed in the said common axis and fixed against movement at one end thereof and formed into a journal eccentric to the said common axis at the other end thereof, said connecting rods secured to said journal for rotation thereabout whereby upon discharge of a barrel in said predetermined position the propellent gas acts upon the said piston and the said cylinder to exert a force upon the said journal to revolve the said plurality of barrels and to present the successive barrel in the said predetermined position.

11. In an automatic gun, a casing, a barrel cluster 45 comprising a plurality of barrels in fixed relation about a common central axis parallel to each, means moturting said cluster on said casing for rotation about said central axis, a cylinder fixed to each respective barrel, there 5 being a gas port between the bore of each barrel and its cylinder, a piston slidably fitting each cylinder, and means including a connecting rod connecting each piston with said frame to exert a torque on said cluster in response to firing of each barrel in succession as said cluster rotates.

12. In an automatic gun, a casing, a barrel cluster comprising a plurality of barrels in fixed equiangular relation about a common axis with which all said barrels are parallel, means mounting said cluster on said casing for rotation about said common axis, a cylinder fixedly attached to each respective barrel, there being a gas port between the bore of each barrel and its cylinder, a piston slidably fitting each cylinder, and means including a con necting rod connected with each piston, for applying torque impulses to said cluster in succession in response to gas pressure in each cylinder as its barrel is fired.

13. In an automatic gun, a casing, a barrel cluster comprising a plurality of barrels in fixed equiangular relation about a common axis with which all said barrels are parallel, means mounting said cluster on said casing for rotation about said common axis, a cylinder fixedly attached to each respective barrel, the longitudinal axis of each said cylinder being normal to, the axis of each respective barrel, a gas port communicating between the bore of each barrel and its cylinder, a piston slidably fitting within each cylinder, a fixed journal mounted eccentric to said common axis and a rod connecting each said piston to said journal for applying torque impulses to said cluster in succession in response to gas pressure in each cylinder as its barrel is fired.

References Cited in the file of this patent UNITED STATES PATENTS 544,657 Browning Aug. 20, 1895 550,262 Ehbets Nov. 26, 1895 594,710 Simpson Nov. 30, 1897 1,424,751 Bangerter Aug. 8, 1922 2,410,848 Waltke Nov. 12, 1946 2,560,292 Kauch July 10, 1951 

